다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Disturbance-observer-based control (DOBC) and related methods have been researched and applied in various industrial sectors in the last four decades. This survey, at first time, gives a systematic and comprehensive tutorial and summary on the existing disturbance/uncertainty estimation and attenuation techniques, most notably, DOBC, active disturbance rejection control, disturbance accommodation control, and composite hierarchical antidisturbance control. In all of these methods, disturbance and uncertainty are, in general, lumped together, and an observation mechanism is employed to estimate the total disturbance. This paper first reviews a number of widely used linear and nonlinear disturbance/uncertainty estimation techniques and then discusses and compares various compensation techniques and the procedures of integrating disturbance/uncertainty compensation with a (predesigned) linear/nonlinear controller. It also provides concise tutorials of the main methods in this area with clear descriptions of their features. The application of this group of methods in various industrial sections is reviewed, with emphasis on the commercialization of some algorithms. The survey is ended with the discussion of future directions.

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Disturbance-Observer-Based Control and Related Methods—An Overview

This paper studies a number of quantized feedback design problems for linear systems. We consider the case where quantizers are static (memoryless). The common aim of these design problems is to stabilize the given system or to achieve certain performance with the coarsest quantization density. Our main discovery is that the classical sector bound approach is nonconservative for studying these design problems. Consequently, we are able to convert many quantized feedback design problems to well-known robust control problems with sector bound uncertainties. In particular, we derive the coarsest quantization densities for stabilization for multiple-input-multiple-output systems in both state feedback and output feedback cases; and we also derive conditions for quantized feedback control for quadratic cost and H/sub /spl infin// performances.

The sector bound approach to quantized feedback control | NOVA. The University of Newcastle's Digital Repository

This work presents a general framework for nonlinear systems subject to disturbances using disturbance observer based control (DOBC) techniques. A two-stage design procedure to improve disturbance attenuation ability of current linear/nonlinear controllers is proposed where the disturbance observer design is separated from the controller design. To facilitate this concept, a nonlinear disturbance observer is developed for disturbances generated by an exogenous system, and global exponential stability is established under certain condition. Furthermore, semiglobal stability condition of the composite controller consisting of a nonlinear controller and the nonlinear disturbance observer is established. The developed method is illustrated by the application to control of a two-link robotic manipulator.

/pdf/disturbance-observer-based-control-for-nonlinear-systems-5gmmz4z7cy.pdf

Disturbance observer based control for nonlinear systems

Stability and L2-gain analysis for switched delay systems: A delay-dependent method

Networks of coupled large scale oscillators have been studied in biology for a number of years. It has been recognized that transient in the nearest neighbor connected networks may take far too long to die out. In the model of mammalian rhythm, it is considered that a few long distance interconnections exist. Typically, these long distance interconnections are considered to occur in a random way. In this study, we discuss the synchronization problem for coupled oscillator networks which can model the mammalian rhythm. Then, the distribution model for the random long distance connections is proposed and is demonstrated by simulation. Furthermore, the proposed oscillator network is applied to the visual model of dragonfly.

Synchronization of Networked Oscillators and Its Application

Backstepping control of a class of nonlinear systems preceded by hysteresis with prandtl-ishlinskii presentations

The nano-stage driven by magnetostrictive actuator is composed of a magnetostrictive actuator and a positioning mechanism (PM). Due to the existence of hysteretic nonlinearity in the magnetostrictive actuator and the friction behavior in the PM, the accurate position control of the nano-stage is a challenging task. This paper discusses the high precision control for the magnetostrictive nano-stage, where the hysteresis is described by Preisach model. The proposed control law ensures the zero output tracking of the controlled stage. Experimental results show the effectiveness of the proposed method.

Advanced control for magnetostrictive actuated nano-stage

The piezo-actuated stage is composed of a piezoelectric actuator (PEA) and a positioning mechanism (PM). Due to the existence of hysteretic nonlinearity in the PEA and the friction behavior in the PM, the accurate position control of the piezo-actuated stage is a challenging task. This paper discusses the continuous-time adaptive control for the piezo-actuated stage, where the hysteresis is described by Prandtl-Ishlinskii model. The proposed control law ensures the zero output tracking of the controlled stage. Experimental results show the effectiveness of the proposed method.

Adaptive control for piezo-actuated stage based on continuous-time approach

A new model reference robust control is proposed for single-input single-output (SISO) minimum-phase dynamical systems with unmatched disturbances, using only the input and output measurements. Based on VSS theory, an 'approximate differentiator' is proposed to estimate a special signal generated by the disturbance. By using the estimated special signal to cancel the influence generated by the disturbance, the intermediate input (a certain order filter of the input) is synthesized on the basis of the Diophantine equation to achieve the model reference purpose. Finally, the real control input is determined by employing the formulated 'approximate differentiator' technique. The output tracking error can be made arbitrarily small without the requirement for a large control energy to be available. Design examples and simulation results are presented to show the superiority and effectiveness of the proposed algorithm.

Xinkai Chen

Papers

Synchronization of Networked Oscillators and Its Application

Backstepping control of a class of nonlinear systems preceded by hysteresis with prandtl-ishlinskii presentations

Advanced control for magnetostrictive actuated nano-stage

Adaptive control for piezo-actuated stage based on continuous-time approach

Model reference robust control for SISO systems with unmatched disturbances